1. Field of the Invention
The present invention relates to a shift lever apparatus for changing a shift range on a vehicle transmission.
2. Description of the Related Art
An example of a shift lever apparatus for changing a shift range on an automatic transmission for a vehicle is disclosed in Japanese Utility Model Application Laid-Open (JP-U) No. 60-126815. In a shift lever of the shift lever apparatus in this disclosure, each of the components is integrally molded using a material in which a thermoplastic synthetic resin is impregnated with glass fibers so as to form the shift lever. Accordingly, this shift lever, being different from a conventional shift lever which has been formed by welding a plurality of metal components or by fastening the components with bolts, is made more compact and lightened. In addition, although this shift lever is molded from a synthetic resin, as it contains glass fibers, it has a high degree of strength.
An ordinary shift lever apparatus comprises a restricting means for restricting an unexpected shift operation from a predetermined shift position (e.g., a shift position corresponding to a reverse range for driving the vehicle driving wheel in reverse) to another shift position (e.g., a shift position corresponding to a parking range for locking the vehicle driving wheel).
This type of restricting means has a detent rod which is accommodated inside the shift lever, which is urged toward a tip end of the shift lever by an urging means such as a compression coil spring, and which can move therein along an urging direction of the urging means and along a direction opposite to the urging direction. Detent pins are formed at an outer peripheral portion of this detent rod so as to protrude therefrom, then penetrate through slit holes or the like which are formed at an outer peripheral portion of the shift lever, and protrude therefrom. On the other hand, side walls, that stand upright from a base member which supports the shift lever, are disposed at the sides of the shift lever. A tip end portion of each of the aforementioned detent pins enters into a detent hole which is formed in the side walls.
As described above, as the detent rod is urged by the urging means, the detent pin normally abuts an inner peripheral portion of the detent hole in a direction in which the urging force of the urging means acts. A wall portion is formed at a portion of the inner peripheral portion of the detent hole in a direction opposite to the direction in which the urging force of the urging means acts. Namely, when the shift lever is located at the aforementioned predetermined position, the detent pins and the wall portion face each other along a rotating direction of the shift lever, and the wall portion restricts the rotational operation of the shift lever to another shift position through the detent pins and the detent rod. When the detent rod is moved so as to oppose the urging force of the urging means by pressing a button provided at a knob or the like, the detent pins are caused to disengage from the wall portion, and a rotational operation of the shift lever to another shift position can be performed.
The strength of the detent pin on its own and the strength obtained through the connection of the detent pin and the detent rod must ensure a strength which is greater than or equal to a level of strength which is able to resist an impact load of the detent pin on abutting against the wall portion of the detent hole during the rotational operation of the shift lever, and for this reason, generally, the detent pin and the detent rod have been formed by welding metal components.
The shift lever of the shift lever apparatus in the Japanese Utility Model Application Laid-Open (JP-U) No. 60-126815 has also been formed in the same manner as this. Namely, since the shift lever has been formed by connecting a metal detent pin to a metal detent rod by welding, from a viewpoint of making the shift lever more compact, there has been room for improvement.